Shea butter

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Shea butter in a small tin for cosmetic use.

Shea butter is a slightly yellowish or ivory colored natural fat extracted from the seed of the African shea tree by crushing and boiling. It is widely used in cosmetics as a moisturizer and salve. Shea butter is edible and may be used in food preparation, or sometimes in the chocolate industry as a substitute for cocoa butter.

The English word shea comes from sí, the tree's name in the Bamana language of Mali. The French name karité comes from ghariti, its equivalent in the Wolof language of Senegal.

Butter extraction and refining

The traditional method of preparing unrefined shea butter consists of the following steps:

• Separating/cracking: The outer pulp of the fruit is removed. When dry, the nut which is the source of shea butter, must be separated from the outer shell. This is a social activity, traditionally done by Women Elders and young girls who sit on the ground and break the shells with a small rock.
• Crushing: To make the shea nuts into butter they must be crushed. Traditionally this is done with a mortar and pestle. It is hard grueling work with the women spending hours lifting the heavy pestles and slamming them down into the mortar to crush the nuts so they can be roasted.
• Roasting: The crushed nuts are then roasted in huge pots over an open wood fire. The pots must be stirred constantly with a wooden paddle so they don't burn. The butter is heavy and stirring it is hot, smoky work, done under the sun. This is where the slight smoky smell of traditional shea butter originates.
• Grinding: The roasted shea nuts are ground into a smoother paste, water is gradually added and the paste is mixed well by hand.
• Separating the oils: The paste is kneaded by hand in large basins and water is gradually added to help separate out the butter oils. As they float to the top the butter oils, which are in a curd state, are taken out and excess water squeezed out. The butter oil curds are then melted in large open pots over a slow fire. A period of slow boiling will remove any remaining water, which boils off as steam.
• Collecting and shaping: The shea butter, which is creamy or golden yellow at this point, is ladled off the top of the pot and put in a cool place to harden. Then it is formed into balls.

Nowadays a mechanical sheller such as the Universal Nut Sheller may be used. The refined butter may be extracted with chemicals such as hexane, or by clay filtering.

Composition and properties

Shea butter extract is a complex fat that contains many non-saponifiable components (substances that cannot be fully converted into soap by treatment with alkali.) oleic acid (40-60%); stearic acid (20-50%); linoleic acid (3-11%); palmitic acid (2-9%); linolenic acid(<1%); arachidic acid(<1%).

Shea butter melts at body temperature and absorbs rapidly into the skin without leaving a greasy feeling.

Uses

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Shea butter soap.

Traditional

In Africa, shea butter is used for cooking oil, as a water proofing wax, for hairdressing and for candle-making; and also as an ingredient of medicinal ointments.

It is also used by makers of traditional African percussion instruments to increase the durability of wood (such as that of carved djembe husks and gourds) and leather binds.

Industrial

The main industrial use of shea butter outside Africa is in cosmetics, such as moisturizer creams and emulsion, and hair conditioners for dry and brittle hair.

It is also used by soapmakers, typically in small amounts (5-7% of the oils in the recipe), because of its property of leaving a small amount of oil in the soap.

Shea butter is also used as an ingredient in chocolate fillings.

Commercial shea butter is now classified into five grades: A (raw or unrefined, extracted using water), B (refined), C (highly refined and extracted with solvents such as hexane), D (lowest uncontaminated grade), E (with contaminants). Commercial grades are A, B, C. The color of raw (grade A) butter ranges from cream (like whipped butter) to grayish yellow, and it has a nutty aroma which is removed in the other grades. Grade C is pure white. Grade A retains the most natural vitamins, especially vitamin A and vitamin E, which are partially lost in the other grades.

Medicinal

Shea butter is used as a base for medicinal ointments, and has been claimed to have anti-inflammatory properties emollient and humectant.

Shea butter has been claimed to be effective treatment for the following conditions: fading scars, eczema, burns, rashes, severely dry skin, dark spots, skin discolorations, chapped lips, stretchmarks, wrinkles, and in lessening the irritation of psoriasis.

Shea butter has been used as a sunblocking lotion, although the level of protection against the sun's ultraviolet radiation is extremely variable, ranging from nothing to approximately SPF 6. However, studies have shown it to reduce the effects of UV damage on the skin. Also, in Ghana shea butter, locally known as nkuto(AKAN) or nku (GA) is used as lotion to protect their skin against the dry Harmattan season.

In Nigeria, shea butter (popularly called 'Ori' in the Yoruba lingua) is used for the management of sinusitis and relief of nasal congestion. This is due to its hydrating properties which helps in relaxing the tension in the face skin thus easing respiration.

References

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